The assignee of the present invention, Setco Sales Company, owns U.S. Pat. Nos. 5,727,095, 5,980,115 and 6,217,219 B1, all of which are entitled “Bearing Seal With Uniform Fluid Purge,” and directed to a unique bearing seal which has proved tremendously successful in increasing the reliability of spindles. Setco sells this patented bearing seal under the trademark AIRSHIELD®. These Setco patents are incorporated herein by reference, in their entireties.
According to one aspect of the prior invention, the bearing seal includes an annular cap located at a first end of a bearing housing, where a shaft exits therefrom. The cap has an internal surface which defines an annular internal volume, and a passage formed therethrough which tangentially intersects the annular volume. This structure allows pressurized purge fluid to be supplied to the annular volume via the passage, to create a circumferentially uniform fluid pressure within the annular volume. This circumferentially uniform pressure prevents ingress of contaminant materials within the bearing.
This prior invention has significantly increased spindle reliability, by reducing downtime caused by failed bearing seals. Such downtime can have critical adverse effects on overall spindle efficiency and throughput.
These prior patents disclose four specific embodiments for achieving the critical benefits of this prior invention. Moreover, these prior patents expressly suggest that the benefits of that prior invention can be obtained in retrofit situations, where an in-place spindle with a failed bearing seal requires the retrofitting of a new bearing seal. These prior patents suggested some general details of how such a retrofitted bearing seal could be achieved. However, those prior patents did not disclose or suggest a specific structure for achieving the benefits of the prior invention with a wide variety of spindles of various size and shape.
It is an object of the present invention to more easily and effectively retrofit bearing seals on in-place spindles.
It is another object of the present invention to more readily accommodate existing spindles of various size and shape with a new and improved bearing seal.
It is still another object of the invention to improve, in a relatively simple and cost-effective manner, the sealing efffectiveness of existing spindles.